1. Technical Field
The invention relates to an electron emission device and a display device using the electron emission device.
2. Discussion of Related Art
Electron emission displays are new, rapidly developing in flat panel display technologies. Compared to conventional technologies, e.g., cathode-ray tube (CRT) and liquid crystal display (LCD) technologies, Field Electron emission Displays (FEDs) are superior in having a wider viewing angle, low energy consumption, a smaller size, and a higher quality display.
Generally, FEDs can be roughly classified into diode type structures and triode type structures. Diode type FEDs has only two electrodes, a cathode and an anode. Diode type FEDs can be used for character display, but are unsatisfactory for applications requiring high-resolution display images, because of they are relatively non-uniform and there is difficulty in controlling their electron emission.
Triode type FEDs were developed from the diode type by adding a gate electrode for controlling electron emission. Triode type FEDs can emit electrons at relatively lower voltages. A conventional triode type electron emission device includes a cathode electrode, a gate electrode spaced from the cathode electrode. Generally, an insulating layer is deposited on the cathode electrode for supporting the gate electrode, e.g., the gate electrode is formed on a top surface of the insulating layer. The cathode electrode includes an emissive material, such as carbon nanotube. The gate electrode includes a plurality of holes toward the emissive material, these holes are called gate holes. In use, different voltages are applied to the cathode electrode and the gate electrode. Electrons are emitted from the emissive material, and then travel through the gate holes in the gate electrode.
The conventional gate electrode is a metal grid, the metal grid has a plurality of gate holes. The small size gate holes make for a more efficient high-resolution electron emission device. Generally, the metal grid can be fabricated using screen-printing or chemical etching methods. Areas of the gate holes in the metal grid are often more than 100 μm2, so the electron emission device cannot satisfy some needs requiring great accuracy. The uniformity of the electric field cannot be improved by decreasing the size of the gate holes, and thus, the performance of electron emission is restricted. Further, the method for making the metal grid requires an etching solution, and the etching solution may be harmful to the environment. Additionally, the grid made by metal material is relatively heavy, and restricts applications of the electron emission device.
What is needed, therefore, is an electron emission device and a display device using the same having high efficiency, high-resolution and light weight.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate at least one embodiment of the present electron emission device and displaying device.